sylph-decoder 801062c933 re: a long voice cue is three presentations of one take, and our guard clips the first
Closes the last open question on the voice regions: why one cue s byte span
decodes to ~2.6x the movie s length.

The port measured, with controls including a cross-movie negative, that a
region s leading chunk is the TAIL of the full-length chunk that follows it --
r = 0.998 at a lag that puts it flush against that chunk s end, residual 16.7 dB
down over 84.5 s. They withdrew their own earlier 0.768, which came from a
search that scored best on the boundary of its own lag range.

Checked it here by an independent route that needs no decoder. If the leading
chunk is the tail of a full-length first stream, the whole leading stream should
be one complete take of chunk 1 s duration. For ADV: 504464 + 808304 = 1312768 B
at chunk 0 s byte rate of 9559.7 B/s is 137.323 s, against chunk 1 s measured
137.324 s. One millisecond over 137 seconds, from byte rates rather than from
envelope correlation.

And the byte structure settles the shape disc-wide. Counting stream starts inside
every inter-descriptor span: 258 hold exactly 1 stream, 28 hold exactly 3, and
nothing holds 2 or any other number. All 20 spans over 1.5 MB are 3-stream. The
95 movie regions decompose 70 + 8 + 17, and the 8 are independently the same 8
the first census found as bank-header-with-3-chunks.

So 359 s = 84.55 + 137.32 + 137.32: three presentations of one take, the first
clipped by resolve_movie_voice_region s own 1.5 MB guard.

Consequences recorded for the port: dropping the leading chunk is removing a
duplicate rather than truncating, so the hedge is lifted; but summing chunk 1
and chunk 2 is wrong, because they are the same take at different gain, not two
stems. Take one stream.

Also flags a coincidence I nearly built on: the 504464 B constant is structural,
not proportional -- ADV s proportional prediction lands within 8 bytes of it and
S00A s is 4305 B out.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
2026-08-29 15:09:40 +00:00

Sylpheed

A clean-room reverse engineering and port project for Project Sylpheed: Arc of Deception (Xbox 360, 2007).

Three things live here, in one repository so that a change spanning them lands as one commit:

The decoders crates/sylpheed-formats — the disc's formats, read and verified disc-wide
The port port/ — a Godot 4 project, plus crates/sylpheed-export which converts a disc into the open asset tree it reads
The corpus docs/re/ — what has been reverse engineered, with its evidence, its retractions and its dead ends

You need your own copy of the game. No game content is in this repository and none ever will be. The exporter reads the disc you supply.

The oracle is the real game

sylpheed-cli and the Explorer are tools for verifying our decoding. They are hypotheses under test and they have been wrong. When something must be checked against the truth, the truth is the game running in Xenia Canary, captured — not any renderer of ours.

This is stated first because getting it backwards is the most expensive mistake this project has made.

Layout

crates/
  sylpheed-formats/   the decoders. Disc-wide verified; the corpus is its spec
  sylpheed-cli/       headless tools -- render a screen, dump a table, probe audio
  sylpheed-viewer/    the Explorer: a human's window onto the disc. STATIC data only
  sylpheed-export/    disc -> the open, moddable asset tree
port/                 the Godot 4 project. Reads open formats ONLY
authored/             decisions that are NOT on the disc, each with its reason
data/
  base/               generated by the exporter. Gitignored, never hand-edited
  mods/               drop-in overrides. Yours
docs/
  re/                 the corpus: findings, refutations, method traps
  game/               how the game is navigated -- menus, modals, flight
  port/               the port's mission, its handoff contract, modding rules
  agents/             how the agent team works together
tools/                capture harnesses, probes, the share tool
exchange/             transient inter-agent files. NOT in git
docker/               the agent containers

Where to start

Xenia Canary is a separate repository: it is a fork tracking upstream, and it carries our instrumentation.

Conventions

Confidence is per claim, never per document: CONFIRMED · 🟡 PROBABLE · HYPOTHESIS · REFUTED. A withdrawn result is kept with its reasoning rather than deleted — that is why the numbers here can be trusted.

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